Method of thionous precipitation.



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" cannot be definitely UNITE srirrns PATENT cr mes.

METHOD .OF THIONOUS PRECIPITATION.

if a new and useful Improvement in Methods of Thionous Precipitation, ot which the following is a specification.

My invention relates toan improvei'ncnt in methods of precipitating copper and sit ver from their solutions and particularly to a 'method of precipitating the same by means of thionites and thionates of iron.

I have discovered that where lliionates or tl'iionites of iron are brought into contact with solutions containing copper and silver. a precipitation of the copper and silver may be eflected in a commercial way. thereby saving a large aniount 01" laborand expense in the metallurgical operations connected with the production of these salts. iihe method of producingthe solution of tliionous and thionic acids 'for' use in this precipitation is immaterial, but I have also discovered that Where asolut-ion. of thiouons or thionicacids or their salts is developed by treatingslags, ierrous sulfid, iroi'i or oxidizedores withsulfurous acids or sulfur smoke scrubbing liquor, a very great saving ot'expense results. By the words thionous acids means to?- imply a group of; acids, such as thiosulfuric (H5 and hyposulfurous, (H SO as mentioned in the chemistry of Prescott & Johnson or HSO of Roscoe & Schorlemmer, or the possible thionous acid H 3 0 of h'lendelieti'. The .oxids of iron used are those found in nature. 'lheir precise chemical nature such as hematite, limonite, oxids of iron derived from these minerals by atmospheric action, those silicates of iron which are easily attacked by weak ends and WlllCll might form oxlds of iron in ldecomposition, and generally all oxide and hydroxids of ironexwpting Fed) specified for there are a great many indefinite compounds of Fe O and H 0, and certain chemists afiirm that there are no two definite compounds or said substances. In the case of the lies in the fact that they are often mixed 1n the ores or materials ,I propose to use.

Where slagis used for the production of thisre-agent which is the cheapest method,

Ipteferably blow the material into wool or otherwise finely divide it. It is then charged Specification of Letters Patent.

Application filed May 22, 1906. Serial No. 318,240.

non-hydrated ends the dltiicul'ty of segregating the oxids' Patented June 8, 1909.

Y intobarrels, vats or other receptacles, and a l solution of sulfur dioxide or smoke scrubbing l liquor is added, or I'eause sulfur smoke to E impinge on the material in the presence of l water. in order to hasten the solution, the i mixture may be agitated, and if desired, l air may be used. to modify the form of the tliionite or tliionate salt. After allowing the suspended matter to settle, the supernatant liquor is drawn (id. and is added in a suitable receptacle to tliesolution ot' the metal heated to any required tempo ature. Where iron sultid or oxidized ore is used to produce the reagent the same general course is pursued, but the term oi" the precipitating agent is neressarily changed totsome extent. 'lhus, for example, in placeol? hie-sulfate, a trithionate or a pei'itathionate may result, or in fact a general variation in the mixture of ditl'erent thionites or thionates, as the .tliionites or thionaies may vary from time to time by reason of incidental oxidation, composition of ore or of the material used, or other changing conditions. The constitution of these salts will also depend upon the kind of sulil urous liquor used, the effect of the atl'l'lOSplltilc action upon the materiah as well as the activity of secondary reactions in the mass, due in general to nascent sulfur arising from the deconiiposition of the more unstable products and the tenn ierature of the soilition. After the supernatant liquor has been drawn off, the metal precipitated is removed and treated in any convenient way.

I am aware that sodium and calcium thi0 sulfates have been used-l es laboratory and commercial agent-s principally for dissolving, but I believe it to be new to use ferric cipitation, and also new to produce them by means of utilizations of the waste products above described.

I claim as my invention:

1. The hereinbefore described method of precipitating copper or silver from their solutions by means of the addition of a liquor containing thio. salts of iron.

2. The hercinbefore described method of precipitating cbpper and silver from their solutions, which consists in treating substancescontaii'iing iron in which the iron is soluble in or capableof being attacked by sulfur dioxid. with a solution of sulfur dioxid where'by a liquor containing thio salts of iron is formal, and in adding such to be precipitated, and the mixed solution th'i ites and thionates for purposes of presues liquor to the solution containing copper and silver whereby these metals are precipitated therefrom.

3. The hereinbefore described method of precipitating copper and silver from their solutions, which consists in treating iron with a solution of sulfur dioxid whereby a liquor containing thio salts of iron is formed, and in adding such liquor to the solution containing copper and silver whereby these metals are precipitated therefrom. v

4. The hereinbefore described method of precipitating copper and silver from their solutions, which consists in treating substances containing iron in which the iron is soluble in or capable of being dissolved in sulfurous liquor derived from smelter smoke, with such liquor whereby a liquid containing thio salts of iron is formed, and in adding such liquor to the solution containing copper and silver whereby these metals are precipitated therefrom.

5. The hereinbefore-described method of precipitating copper and silver from their solutions/which consists in treating iron with the sulfurous liquor derived from smelter smoke, whereby a liquor containing thio-salts of iron is formed, and in adding such liquor tot-he solution containing copper and silver, whereby these metals are precipitated therefrom.

' 6. The hereinbcfore described method of precipitating copper and silver from their solutions, which consists in treating salts of iron substantially of the character described soluble in or capable of being attacked by sulfur dioxid,'with solutions developed from the sulfurous liquor derived from smelter smoke whereby a liquor containing thio salts of iron is formed, and inadding such liquor to the solution containing copper and silver whereby these metals are precipitated therefrom.

7. The hereinbefore described method of precipitating copper and silver from their solution. which consists in treating salts of iron substantially of the characterllescribed soluble or capable of being attacked by sulfur dioxid, with solutions developed by the addition of sulfurous acid to substances containing oxid of iron soluble in sulfur dioxid solutions whereby a liquor containing thio salts of iron is formed, and in adding such liquor to the solution containing copp r and silver whereby these metals are precipitated therefrom.

ln testimony, that I claim the foregoing 

